@mixin box-shadow($level: default, $color: default) {
  @if $color == default {
    $color: #000;
  }
  @if $level == 1 or $level == default {
    box-shadow: 0 2px 10px rgba($color, 0.15);
  }
  @if $level == 2 {
    box-shadow: 0 2px 4px rgba($color, .12), 0 2px 8px rgba($color, .06), 0 2px 10px rgba($color, .2);
  }
  @if $level == 3 {
    box-shadow: 0 4px 4px rgba($color, .16), 0 2px 8px rgba($color, .1), 0 4px 12px rgba($color, .25);
  }
}